Conventionally, a cooling system for adjusting a temperature of a device or the like by circulating a liquid coolant has been known (see, for example, Patent Document 1). The cooling system described in Patent Document 1 includes a chiller and a heat exchanger. The cooling system supplies a circulating coolant to a primary coil of the heat exchanger and a low-temperature coolant generated in the chiller to a secondary coil of the heat exchanger to perform a cooling process through heat exchange therebetween.    Patent Document 1: Japanese Patent Laid-open Publication No. H08-293479
The cooling system described in Patent Document 1 may need a large-sized chiller or a long passageway for heat exchange depending on a required cooling temperature. Further, the heat exchanger or a line connecting the chiller to the heat exchanger needs to be heat-insulated. Thus, a size of the cooling system tends to increase depending on a required cooling temperature. In the art to which the present disclosure relates, there is demanded a cooling system and a cooling method capable of controlling a cooling temperature with a simple configuration.